The 55-mile-long river known today as the Sandy, Captain William Clark called the “Quick Sand river” after attempting to cross the shallows at its mouth – and getting stuck.

Clark wrote in his journal for November 3, 1805: “I arrived at the entrance of a river which appeared to scatter over a sand bar, the bottom of which I could see quite across and did not appear to be 4 inches deep in any part.” He attempted to wade the stream, “but to my astonishment found the bottom a quick sand, and impassable.” He called to the canoes and hitched a ride, then after a meal of goose and venison – the hunters had been successful; the explorers had noted the great numbers of waterfowl in the area -- he and Lewis walked up the river about a mile and half, Clark describing it as a “verry Considerable Stream” with two channels and two mouths forming an island about three miles in length.

The area was populated by different tribes when Lewis and Clark came through. Upper Chinook tribes lived along the Columbia from the Cowlitz River to The Dalles. Of these, the Multnomah and Clackamas bands lived west of the Sandy, and the Wasco band lived east of the river.

The Sandy River begins at Reid Glacier on the southwest slope of Mount Hood and flows generally west and north to its confluence with the Columbia just east of Troutdale. The lower mouth is at Columbia River Mile 120.5 and the upper mouth is at River Mile 123. At the time of Lewis and Clark, the Sandy was still ejecting large volumes of volcanic ash and sand from the last major eruption of Mount Hood, which probably occurred in the 1790s, forming the Sandy River Delta, today a popular recreation area.

The Sandy, just 25 miles or so east of Portland, long has been a popular recreational destination. Dodge Park, at the confluence of the Bull Run River and the main Sandy channel, was a popular beach and cooling-off spot for swimmers and picnickners as long ago as the 1920s, when the park could be reached by auto or an electric train from Portland. Today, approximately 25 miles of the Sandy is designated wild, scenic, or recreational. A total of 12.5 miles of the river between Dodge Park and Dabney State Park, has been designated an Oregon State Scenic Waterway and a federal Wild and Scenic River.

The Sandy, or more precisely one of its tributaries, the Bull Run River, became the water source for Portland, and continues to this day. Portland, founded in 1851, got its drinking water from the Willamette River through the 1880s, when it became clear that the growing city would soon outgrow its Willamette supply, which occasionally was fouled with sewage. In 1891, the Oregon Legislature authorized the city to sell bonds to pay to develop a water supply from the Bull Run River, and it began delivering water to Portland in 1895.

For more than 90 years, the Sandy also was a hydropower workhorse for Portland General Electric Company. The Bull Run Hydroelectric Project, built in 1912, was a 22-megawatt hydropower plant served by two impoundments -- Marmot Dam, 27 miles from its confluence with the Columbia, and Little Sandy Dam on the Little Sandy River. The power plant closed in 1999.

The 47-foot high Marmot Dam and 16-foot high Little Sandy Dam were removed by the utility in 2007 and 2008, respectively, allowing the Sandy to run free for the first time in 96 years, and flushing an estimated 900,000 cubic yards of sediment that had built up behind Marmot Dam. View a United State Geological Survey time-lapse video of Marmot Dam removal here. The dams prevented salmon, steelhead, and trout from migrating to some 280 miles of habitat, primarily on the stretch of river above Marmot Dam. PGE decided the $20 million potential cost of retrofitting the dams for fish passage, plus enhancement measures that would be required by the Federal Energy Regulatory Commission as part of a revised operating license, was too high, and that dam removal was cheaper and better for the fish, too.

Soon salmon were back in the Little Sandy, where ideal spawning and rearing habitat existed. PGE also donated 1,500 acres of the former hydroelectric projects property as a nature preserve. Ten years of free-flowing river has been good for fish, the Oregon Department of Fish and Wildlife reported in 2017. The Sandy has been seeing increasingly strong returns of spring Chinook, in some cases double what they were a decade before Marmot Dam was removed.

This entry originally was written for The Oregon Encyclopedia